Brain Scans Show Differences in Cocaine Addicts

ByABC News
May 28, 2009, 6:02 PM

May 29 -- THURSDAY, May 28 (HealthDay News) --Cocaine users appear to have less activity in the parts of their brains that monitor behaviors and emotions, a finding that researchers think may make them more vulnerable to addiction to the drug, a new research shows.

Using MRI scans, the researchers saw there were issues in these regions of the brain when cocaine users were given a test in which fast, correct answers -- some dealing specifically with drug use -- were rewarded with money. The issues persisted even when the addicts did as well as non-cocaine users on these tests.

"Whether these brain differences are an underlying cause or a consequence of addiction, the brain regions involved should be considered targets for new kinds of treatments aimed at improving function and self-regulatory control," study author Rita Goldstein, a psychologist at the U.S. Department of Energy's Brookhaven National Laboratory, said in a news release issued by the lab.

The study results appear online this week in the Proceedings of the National Academy of Sciences.

In the experiment, a group of active cocaine users and demographically similarly but healthy non-users had to push a button that corresponded to a word related to either drug use (e.g., crack, addict) or a neutral term, depending on the scenario. Fast, accurate answers could earn the test subjects up to a maximum of $75 for the entire experiment.

Brain imaging showed that the part of the brain that normally becomes active when people monitor their own behavior was far quieter in the cocaine users, especially during the parts of the test in which no monetary rewards were being offered and only neutral terms were being used -- sections considered the least "interesting," according to the researchers. Participants who used cocaine most often during the previous month showed the least activity in this area of the brain.

During the section of the test of most interest to the cocaine users -- in which they could earn money for their answers and the terms being used were drug-related -- activity was much lower than their healthy peers in a part of the brain that usually becomes quiet when a person is suppressing emotions. This, the researchers said, suggests the cocaine users were trying to fight off drug cravings to focus on the succeeding at the test.